Brad Keselowski won his first NASCAR Sprint Cup Series championship by 39 points over Clint Bowyer, with five-time champion Jimmie Johnson third, 40 points back of Keselowski.

What the final standings don't show, however, was just how perilously close Keselowski was to losing a championship he controlled until divergent pit strategies late in Sunday's Ford EcoBoost 400 at Homestead-Miami Speedway put his title in jeopardy.

On Lap 158, the No. 2 Penske Dodge team made a fundamental mistake in not covering Johnson's move when the No. 48 Chevrolet came to pit road to top off the fuel tank under the third and final caution of the race.

That put Keselowski in the position of needing two more pit stops to Johnson's one when the race restarted on Lap 162. Why didn't Keselowski insist on pitting behind Johnson?

"It was a very complex situation," Keselowski told the NASCAR Wire Service after a late-night photo shoot on the backstretch. "I didn't have a full understanding of the situation, and I was told not to. I made the wrong call. I should have vetoed it, and I didn't."

In retrospect, Keselowski would have preferred more detailed information from his team, information that would have helped him make the right call.

"Keeping things from me does not help me not get freaked out," Keselowski said. "I want to know what's going on. I want the ball. I want to know what the score is."

After he pitted on Lap 205, Keselowski found out what the score was. He was running 23rd, a lap down to Johnson, who had taken the lead on Lap 202. Keselowski did a quick calculation and followed it with an expletive.

"That's where we'll cycle out (after a final pit stop)," he radioed to crew chief Paul Wolfe.

With Johnson likely to win the race, 23rd wouldn't be good enough to win the championship. Knowing he would need to finish no worse than 16th, Keselowski turned up the wick.

But fate intervened. When Johnson pitted on Lap 214, he left his stall with a loose lug nut. That required a return trip to pit road, which cost him a lap and gave Keselowski breathing room. After the second visit, Johnson's Chevy sustained a punctured oil line and subsequent gear failure that ended his night, making a champion of Keselowski with 21 laps left in the race.

Given the sudden and totally unexpected nature of Johnson's problems, one might think Keselowski's title was meant to be.

"I don't know," Keselowski said. "One day, if I'm lucky enough to be upstairs and have a beer with my maker, I'll ask him that."

Even with Johnson in the garage, Keselowski was determined to drive to 16th to allay talk that he had received a gift.

"That's why I drove my ass off even after he broke to make sure we did that -- because I didn't want to hear that," Keselowski said.

In a broader sense, Keselowski's title may be the point of demarcation for a significant transition in the sport. Certainly, it dealt a serious blow to Johnson's vision of his own legacy.

Before his Chase for the NASCAR Sprint Cup started to go awry in the next-to-last race at Phoenix, Johnson -- in a rare statement of personal ambition -- told reporters he wanted to be remembered as the greatest driver ever to sit in a stock car. The best way to do that, Johnson offered, would be to win an unprecedented eight championships.

The loss to Keselowski at Homestead put a serious crimp in Johnson's plans -- and he knew it.

"It (stinks) to be close and not get it," Johnson said. "That's just the way it is. The statement I made about the eight championships is on that big wish list that ... we all have a wish list. The reality of that isn't something that motivates me, and I'm not focused on it or think about that number.

"It was really to give everybody an answer, because everybody would ask me, 'What next?' "

Johnson's demurral aside, Keselowski's victory may represent the sort of changing of the guard that occurred when Jeff Gordon brought Johnson into the sport just over a decade ago.

Gordon was on the way to the 2001 championship, his fourth, when he lobbied car owner Rick Hendrick and sponsor Lowe's to take a chance on Johnson. In the 11 years thereafter, Johnson has collected five titles, Gordon none.

Asked whether his championship might be another watershed transition, Keselowski paused for a moment.

"Whoa, I don't know about that one," he said. "That's a tough question to answer. It'd be a lot easier if I did it again.